Year Percent 1950 17.47015 1955 19.21324 1960 19.02345 1965 18.93517 1970 18.68509 1975 18.82694 1980 19.40716 1985 19.47955 1990 18.6248 1995 17.90196 2000 17.37734 2005 17.14965 2010 17.4125 2015 17.18128 2020 16.04924 2025 15.03374 2030 14.24902 2035 13.65736 2040 13.12486 2045 12.54106 2050 11.92519 2055 11.30538 2060 10.74157 2065 10.25844 2070 9.82947 2075 9.40513 2080 8.98904 2085 8.58272 2090 8.1749 2095 7.8117 2100 7.47052